In Microsoft SQL Server 2014, you run a SELECT query that generates a parallel batch-mode scan (typically scanning a columnstore index). In some cases, the batch-mode scan may be involved in a deadlock situation. In this case, the deadlock is not resolved automatically.
This problem occurs when a new deadlock cannot be detected and therefore triggers a blocking scenario.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.